I bought it last night. Yes, it's very slow updating. As I said I only got it last night, I'm wondering if it's smart enough to update the complication by time of day. i.e. Work in the AM then Home in the PM. From what I can tell it has to be changed manually.

It does seem slow to update. I'm not entirely sure how it suppose to work. I put in a address that's says 8 min from home. Drove about half way there put the destination address in again and it it to a few minutes to recalculate. I'm not sure if it suppose to recalculate while driving.
I've had the app before  Watch was released.